Strange udev camera problem and solution?

[Matthew Flaschen]

Paul Thompson wrote:
> When I plug my camera's into my PC's (Cannon IXUS55 and a G5
> Powershot) usb port I get the following message when the Import
> Photo's dialog comes up:-
> 
> An error occurred in the io-library ('Could not claim the USB
> device'): Could not claim interface 0 (Operation not permitted). Make
> sure no other program or kernel module (such as sdc2xx, stv680,
> spca50x) is using the device and you have read/write access to the
> device.
> 
> So I Googled and found this:
> 
> http://ubuntuforums.org/showthread.php?t=340271  AND
> http://commandline.org.uk/2007/my-day-with-ubuntu-edgy-eft/#comment-18946
> 
> Did what they advised but no joy. So I had a closer look at
> 45-libgphoto2.rules and found this at the top:
> 
> # udev rules file for libgphoto2 devices (udev < 0.98)
> #
> BUS!="usb*", GOTO="libgphoto2_rules_end"
> ACTION!="add", GOTO="libgphoto2_rules_end"
> 
> This BUS! instruction (as I understand it) is telling it to go to the
> end of the rules and the rules are never checked! I comented out the
> BUS! instruction and now everything is working just fine.

Not to imply I know what I'm talking about :), but it says BUS!="usb".
When it processes a USB camera, BUS should equal usb, right?  Well,
that's probably what was going through the head of the person who
drafted those rules.  Why it doesn't work, I have no idea.  However, in
Dapper it says:

SUBSYSTEM!="usb_device", GOTO="libgphoto2_rules_end"

I would recommend trying that, because checking all those rules for
every device probably slows down the system.

Matt Flaschen